<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT    MIT License
 * @link    http://codeigniter.com
 * @since    Version 3.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * SQLite3 Database Adapter Class
 *
 * Note: _DB is an extender class that the app controller
 * creates dynamically based on whether the query builder
 * class is being used or not.
 *
 * @package        CodeIgniter
 * @subpackage    Drivers
 * @category    Database
 * @author        Andrey Andreev
 * @link        http://codeigniter.com/user_guide/database/
 */
class CI_DB_sqlite3_driver extends CI_DB {

    /**
     * Database driver
     *
     * @var    string
     */
    public $dbdriver = 'sqlite3';

    // --------------------------------------------------------------------

    /**
     * ORDER BY random keyword
     *
     * @var    array
     */
    protected $_random_keyword = array('RANDOM()', 'RANDOM()');

    // --------------------------------------------------------------------

    /**
     * Non-persistent database connection
     *
     * @param    bool    $persistent
     * @return    SQLite3
     */
    public function db_connect($persistent = FALSE)
    {
        if ($persistent)
        {
            log_message('debug', 'SQLite3 doesn\'t support persistent connections');
        }

        try
        {
            return ( ! $this->password)
                ? new SQLite3($this->database)
                : new SQLite3($this->database, SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE, $this->password);
        }
        catch (Exception $e)
        {
            return FALSE;
        }
    }

    // --------------------------------------------------------------------

    /**
     * Database version number
     *
     * @return    string
     */
    public function version()
    {
        if (isset($this->data_cache['version']))
        {
            return $this->data_cache['version'];
        }

        $version = SQLite3::version();
        return $this->data_cache['version'] = $version['versionString'];
    }

    // --------------------------------------------------------------------

    /**
     * Execute the query
     *
     * @todo    Implement use of SQLite3::querySingle(), if needed
     * @param    string    $sql
     * @return    mixed    SQLite3Result object or bool
     */
    protected function _execute($sql)
    {
        return $this->is_write_type($sql)
            ? $this->conn_id->exec($sql)
            : $this->conn_id->query($sql);
    }

    // --------------------------------------------------------------------

    /**
     * Begin Transaction
     *
     * @param    bool    $test_mode
     * @return    bool
     */
    public function trans_begin($test_mode = FALSE)
    {
        // When transactions are nested we only begin/commit/rollback the outermost ones
        if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
        {
            return TRUE;
        }

        // Reset the transaction failure flag.
        // If the $test_mode flag is set to TRUE transactions will be rolled back
        // even if the queries produce a successful result.
        $this->_trans_failure = ($test_mode === TRUE);

        return $this->conn_id->exec('BEGIN TRANSACTION');
    }

    // --------------------------------------------------------------------

    /**
     * Commit Transaction
     *
     * @return    bool
     */
    public function trans_commit()
    {
        // When transactions are nested we only begin/commit/rollback the outermost ones
        if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
        {
            return TRUE;
        }

        return $this->conn_id->exec('END TRANSACTION');
    }

    // --------------------------------------------------------------------

    /**
     * Rollback Transaction
     *
     * @return    bool
     */
    public function trans_rollback()
    {
        // When transactions are nested we only begin/commit/rollback the outermost ones
        if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
        {
            return TRUE;
        }

        return $this->conn_id->exec('ROLLBACK');
    }

    // --------------------------------------------------------------------

    /**
     * Platform-dependant string escape
     *
     * @param    string
     * @return    string
     */
    protected function _escape_str($str)
    {
        return $this->conn_id->escapeString($str);
    }

    // --------------------------------------------------------------------

    /**
     * Affected Rows
     *
     * @return    int
     */
    public function affected_rows()
    {
        return $this->conn_id->changes();
    }

    // --------------------------------------------------------------------

    /**
     * Insert ID
     *
     * @return    int
     */
    public function insert_id()
    {
        return $this->conn_id->lastInsertRowID();
    }

    // --------------------------------------------------------------------

    /**
     * Show table query
     *
     * Generates a platform-specific query string so that the table names can be fetched
     *
     * @param    bool    $prefix_limit
     * @return    string
     */
    protected function _list_tables($prefix_limit = FALSE)
    {
        return 'SELECT "NAME" FROM "SQLITE_MASTER" WHERE "TYPE" = \'table\''
            .(($prefix_limit !== FALSE && $this->dbprefix != '')
                ? ' AND "NAME" LIKE \''.$this->escape_like_str($this->dbprefix).'%\' '.sprintf($this->_like_escape_str, $this->_like_escape_chr)
                : '');
    }

    // --------------------------------------------------------------------

    /**
     * Show column query
     *
     * Generates a platform-specific query string so that the column names can be fetched
     *
     * @param    string    $table
     * @return    string
     */
    protected function _list_columns($table = '')
    {
        // Not supported
        return FALSE;
    }

    // --------------------------------------------------------------------

    /**
     * Returns an object with field data
     *
     * @param    string    $table
     * @return    array
     */
    public function field_data($table)
    {
        if (($query = $this->query('PRAGMA TABLE_INFO('.$this->protect_identifiers($table, TRUE, NULL, FALSE).')')) === FALSE)
        {
            return FALSE;
        }

        $query = $query->result_array();
        if (empty($query))
        {
            return FALSE;
        }

        $retval = array();
        for ($i = 0, $c = count($query); $i < $c; $i++)
        {
            $retval[$i]            = new stdClass();
            $retval[$i]->name        = $query[$i]['name'];
            $retval[$i]->type        = $query[$i]['type'];
            $retval[$i]->max_length        = NULL;
            $retval[$i]->default        = $query[$i]['dflt_value'];
            $retval[$i]->primary_key    = isset($query[$i]['pk']) ? (int) $query[$i]['pk'] : 0;
        }

        return $retval;
    }

    // --------------------------------------------------------------------

    /**
     * Error
     *
     * Returns an array containing code and message of the last
     * database error that has occured.
     *
     * @return    array
     */
    public function error()
    {
        return array('code' => $this->conn_id->lastErrorCode(), 'message' => $this->conn_id->lastErrorMsg());
    }

    // --------------------------------------------------------------------

    /**
     * Replace statement
     *
     * Generates a platform-specific replace string from the supplied data
     *
     * @param    string    $table    Table name
     * @param    array    $keys    INSERT keys
     * @param    array    $values    INSERT values
     * @return    string
     */
    protected function _replace($table, $keys, $values)
    {
        return 'INSERT OR '.parent::_replace($table, $keys, $values);
    }

    // --------------------------------------------------------------------

    /**
     * Truncate statement
     *
     * Generates a platform-specific truncate string from the supplied data
     *
     * If the database does not support the TRUNCATE statement,
     * then this method maps to 'DELETE FROM table'
     *
     * @param    string    $table
     * @return    string
     */
    protected function _truncate($table)
    {
        return 'DELETE FROM '.$table;
    }

    // --------------------------------------------------------------------

    /**
     * Close DB Connection
     *
     * @return    void
     */
    protected function _close()
    {
        $this->conn_id->close();
    }

}
